<!--
 * @Author: susu 1628469970@qq.com
 * @Date: 2022-08-27 23:23:32
 * @LastEditors: susu 1628469970@qq.com
 * @LastEditTime: 2022-08-28 18:48:05
 * @FilePath: \css_demos\web\css3动画\圆弧转动.html
 * @Description: 圆弧转动动画
-->
<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>圆弧转动</title>
</head>
<link rel="stylesheet" href="../common.css">
<style>
    :root {
        --color: orange;
        --lineColor: rgba(102, 163, 224, .2);
    }

    body {
        background: #222;
        overflow: hidden;
    }

    section {
        position: relative;
        width: 200px;
        height: 200px;
    }

    section::before {
        content: '';
        position: absolute;
        height: 10px;
        width: 10px;
        border-radius: 100%;
        border-top: 1px solid orange;
        /* border-bottom: 1px solid orange; */
        top: 50%;
        left: 50%;
        margin-top: -5px;
        margin-left: -5px;
        animation: turn 1s infinite linear;
        filter:
            drop-shadow(0 0 2px var(--color)) drop-shadow(0 0 5px var(--color)) drop-shadow(0 0 10px var(--color)) drop-shadow(0 0 20px var(--color));
    }

    /* section::after {
        content: '';
        position: absolute;
        height: 6px;
        width: 6px;
        border-radius: 100%;
        background-color: #fff;
        top: 50%;
        left: 50%;
        margin-top: -3px;
        margin-left: -3px;
    } */

    .box,
    .box::after,
    .box::before {
        border: 2px solid var(--lineColor);
        border-left: 2px solid var(--color);
        border-right: 2px solid var(--color);
        border-radius: 50%;
    }

    .box::after,
    .box::before {
        position: absolute;
        content: '';
        left: 50%;
        top: 50%;
    }

    .box {
        width: 200px;
        height: 200px;
        position: relative;
        animation: turn 1s linear infinite;
        transform-origin: 50% 50%;
    }

    .box::before {
        width: 180px;
        height: 180px;
        margin-top: -90px;
        margin-left: -90px;
        /* animation: turn 1s linear infinite reverse; */
        /* 伪元素将继承父元素的动画，设置动画reverse，反向变换，可实现木有动画的效果,或重写动画效果 */
        animation: turn2 1.25s linear infinite;
    }

    .box::after {
        width: 160px;
        height: 160px;
        margin-top: -80px;
        margin-left: -80px;
        animation: turn 1.5s linear infinite;
    }

    .box-circle,
    .box-circle1,
    .box-circle2 {
        border: 2px solid var(--color);
        opacity: .9;
        border-radius: 50%;
        position: absolute;
        left: 50%;
        top: 50%;
        transform-origin: 50% 50%;
        transform: translate(-50%, -50%);
        width: 100px;
        height: 100px;
        animation: rotate 3s linear infinite;
    }

    .box-circle {
        animation-delay: 0.2s;
        /* transform: translate(-50%, -50%) rotate3D(1, 0, 0, -120deg); */
    }

    .box-circle1 {
        animation-delay: 1.2s;
        /* transform: translate(-50%, -50%) rotate3D(0.5, 0.5, 1, -260deg); */
    }

    .box-circle2 {
        animation-delay: 2.2s;
    }

    @keyframes turn {
        100% {
            transform: rotateZ(-1turn);
        }
    }

    @keyframes turn2 {
        100% {
            transform: rotateZ(1turn);
        }
    }

    @keyframes rotate {
        100% {
            border: none;
            border-top: 2px solid var(--color);
            border-bottom: 2px solid var(--color);
            transform: translate(-50%, -50%) rotate3d(.5, 0.5, 0.5, -720deg);
        }
    }
</style>

<body>
    <section>
        <div class="box"></div>
        <div class="box-circle"></div>
        <div class="box-circle1"></div>
        <div class="box-circle2"></div>
    </section>
</body>

</html>